Start-stop repeater



Mardi 27, 1951 R, M, M, QBERMAN 2,546,369

START-STOP REPEATER Filed Sept. 5, 1947 INI 'PINTOR Patented Mar. Z7, 1951 UNITED STATES PATENT OFFICE Application September 5, 1947, Serial No. 772,407 In the Netherlands October 6, 1942 Section 1, Public Law 690, August 8, 1946 Patent expires October 6, 1962 3 Claims.

The invention relates to telegraph systems and more particularly to a receiving arrangement therefor.

It is known that telegraph signals after being transmitted over long conductors become distorted from their original shape by lengthening and shortening of the marks and/or spaces and that for this reason it is favorable in receiving devices to make use of only small fractions in the middle of the said marks and spaces, thus avoiding the distorted parts. The intelligence thus gathered from the incoming signal can be utilized in various ways for different purposes such as regenerative repeating, recording in relay or rotary registers or tape perforations and teleprinting.

The object of the invention is to provide a simple and reliable receiving arrangement for telegraph signals.

According to the invention a current controlled by the incoming signal is sent through a winding of a preferably polarized relay, having two stable positions. In another Winding of the same relay fixing currents from local sources can be applied, the direction of these fixing currents being dependent'on the position of the armature and having the effect of iirmly holding the armature in the given position with such energy that the incoming signal cannot change the armatures position. By means of short interruptions or suppressions of the xing current the signal controlled winding is enabled to shift the relay, provided that the signals mark or space requires such shifting. The suppression time must be long enough for the receiving relay to overcome the balancing point.

Both the position of the reception relay armature and the alternatively directed fixing currents constitute amplied and regenerated reproductions ci the original signal, with a lag of about one half of a signal element and free from the distortions inherent to the input signal; and both these phenomena can be utilized for various purposes not essential to the invention.

The suppressing means for the fixing current can be carried out in several ways known per se in the art, e. g. as a rotary switch, but the inventor prefers a vibrating relay having an armature movable between` interconnected changeover contacts'thus restricting the interruption time of the free movement.

The novel features which I consider as characteristic for my invention are set forth in particular in the appended claims. The invention itself, however, both' as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a wiring diagram illustrating the general principle of the invention, and

Fig. 2 is a diagram in which by way of example the preferred embodiment of the timing and synchronizing devices is shown for the 5-unit start-stop teleprinter code with 20 milliseconds signal elements.

Referring now to the drawings and iirst to Fig. l

'1, OR is the reception relay having two windings: the fixing winding I and the reception winding 2. In the shown position battery BI sends a current over back contact or through winding I; the direction of this current is so chosen that the armature is pressed firmly against said back contact. Should the armature be placed against the front contact, then a current of opposite direction and supplied by the other battery B2 would iiow in the fixing winding pressing the armature against said front contact.

Interruption of the xing current in winding I is performed by the timing device TD. Be it assumed for the present example that TD comprises a relay having an armature k2 between change-over contacts. When swingingsaid armature has a short free period of no contact. If during such an interruption a signal element makes relay OR to skip, subsequent restoring of contact k2 will result in reversed current iixing or in the new position. SD represents a synchronizing device.

Any of the single wire parts II of the iixing circuit can be utilized for the purposes mentioned above, but also the branches I2 and I3 can render useful services, e. g. for relay registering.

In Fig. 2 more detail is given of the timing and synchronizing devices. Their task is to ensure regular swinging of armature k2 and to put the circuit-interruptions in the approximate middle of the signals elements. For this example the Teletype five-unit code is chosen and it will be assumed that the receiver is part of a regenerafv tive repeater.

The timing device comprises the polarized relay K in combination with condenser Cl and adjustable resistors W3 and W4.

The synchronizing device comprises the startstop relay AR and the counting relays A to E.

The drawing shows the relays AR and A to E in de-energized position. Relay AR is connected between two plus-poles in the circuit: -l-BS, relay AR, back contact arl, back contact or, -I-BI; this represents a short circuit if BI and B3 are identical. Relay K is energized by battery B2 over resistor W3 and back contact m5. This means that armature k2 is on its back Contact as shown and the sender relay ZR is energized by battery BI over back contact ar2 and back contact k2. Consequently, sender armature er is connected to BI by its front contact as shown, and a signal current of stop character is flowing into the line by terminal Y. The fixing winding I is also de-energized because both the front contacts k2 and a12 are open.

When the start element of a signal arrives at terminal X and energizes (eventually after previous amplification) the reception winding 2 of relay OR, this relay operates and brings the start-stop relay AR between batteries B3 and B2 of opposite polarity in the circuit: -I-BB, relay AR, back contact arl, front contact or, -B2. Relay AR is energized and holds itself over the circuit -I-BS, relay AR, front contact arl, back contact e2, -B2, and will thus remain operative until the fifth counting relay E announces the end of the signal.

Front contact m2 completes the branch I3 and closes the fixing current circuit as it was given in Fig. 1, with about milliseconds delay after the operation of relay OR; reversed current from battery B2 is sent to the sender relay ZR over the circuit: B2, front contact or, winding I, front contact a12, back contact k2, relay ZR, ground; .and relay ZR repeats the start element.

Simultaneously contact m5 reverses the current in relay K, now supplied by BI over back contact lcI, resistor W4 and front contact m5, but relay K by combined action of condenser -CI and adjustable resistor W4 has a delay of about milliseconds, and therefore the swing of armature k2 occurs in the middle of the first signal unit. If this is a mark of same character as start, contacts or and .er remain in the start position; should the first unit be a space then both contacts or and er will change.

The first swing of armature cI brings a negative impulse from B2 over front contact k! rectifier SI, back Contact d2 and back contact b2 to the rst counting relay A, which holds itself over its contact al and back contacts bl, cI, dI and eI. f

Simultaneously, the current in relay K is reversed and again supplied by B2. Relay K will thus by contact kl reverse its own current automatically in 20 milliseconds intervals. Negative and positive impulses are sent through rectifiers SI and S2 alternatively. The first (negative) impulse corresponding with the 'first signal unit actuates relay A as described above. The second impulse is positive and actuates relay .B over -I- contact bl, back contact ki, rectier S2, back `Contact c2 and front contact d2; relay B holds itself over front contact bl, but breaks the exist- .ing holding circuit of relay A in back contact b I. The third, fourth and fth units are counted by C, D and E in an obvious way and E interrupts the holding circuit of relay AR as already mentioned. The fifth unit indicated by a swing of armature 7c! to battery B2, and the Cle-energizing of relay AR keeps the same battery B2 connected with relay K, over resistor W3 and back contact m5. It follows that relay K performs a sixth interval of 20 milliseconds independent of the restoring delay of relay AR, if it is Aassumed that W3 and We are of substantially equal value. The sixth swing of armature k2 back to the normal shown position produces the repeated stop unit at terminal Y: -l-BI, back contact ar2, back contact k2, relay ZR, ground; relay ZR removes its armature sr over to the -I-BI contact and the arrangement is completely restored to the normal position as shown in the drawing, being ready for awaiting the next start element.

lt will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of receiving arrangements differing from the types described above.

While I have illustrated and described the invention as embodied in receiving arrangements for telegraph code signals and similar purposes, I do not intend to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of my invention.

'Without further analysis, the foregoing will so fully reveal vthe gist of my invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What I vclaim as new and desire to secure by Letters Patent, is:

i. A receiving arrangement for telegraph code signals comprising in combination a reception r iay having a signal operated reception winding; an armature, and a fixing winding connected in series with said armature; two change-over contacts cooperating with said armature in the stable position thereof; two sources vof current being connected with different polarities to the respective change-over contacts of said relay for supplying fixing currents of alternative directions to said fixing winding, said fixing currents overruling the signal controlled currents in said reception winding; a timing device for periodicaily suppressing the preponderance of said fixing winding over said signal reception winding during a predetermined fraction of each period; and means for synchronizing said timing device with the signal.

2. A receiving arrangement for telegraph code signals comprising in combination a reception relay having a signal operated reception winding, an armature, and a fixing winding connected in series with said. armature; two change-over contacts cooperating with said armature in the stable position thereof; two sources of current being connected with different polarities to the respective change-over contacts of said relay for supplying fixing currents of alternative directions to said fixing winding, said fixing currents overruling the signal controlled currents in said reception winding; a timing device including a vibrating relay having an armature movable between two interconnected contacts, said armature of said vibrating relay being coupled with the current of said fixing winding and periodically interrupting the current of said fixing winding during its swings, if the interruptions are of a predetermined sufficiently long duration to allow the operation of said reception winding in response to the signals prevailing code element; and means for synchronizing said timing device with the signal.

3. A receiving arrangement for telegraph signals in a. start-stop code system comprising in combination a reception relay having asignal operated reception Winding, an armature and a ixingv winding connected in series with said armature; two change-over contacts cooperating with said armature in the stable positio-n thereof; two sources of current being connected with different polarities to the respective change-over contacts of said relay for supplying fixing currents of alternative directions to said fixing winding, said fixing currents overruling the signal controlled currents in said reception winding; a timing device including a vibrating relay having anarmature movable between two interconnected co-ntacts, said armature being coupled with the current of said fixing winding and periodically interrupting the current of said xing winding during its swings, if the interruptions are of a predetermined suirlciently long duration to allow the 20 iii AREFEmiNCEs CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,000,078 Cummings et al. Aug. 8, 1911 1,771,446 Parker July 29, 1930 1,970,455 Humphries Aug. 14, 1934 2,413,741 Young Jan. 7, 1947 2,433,362 Hartley et al. Dec. 30, 1947 2,468,065l Hartley Apr. 26, 1949 

